Postretirement Benefits (Estimated Total Future Postretirement Benefit Payments, Net Of Participant Contributions And Estimated Future Medicare Part D Subsidy Receipts) (Details) (U.S. Postretirement Benefit Plans [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011
U.S. Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Payments, 2012	$ 55
Benefit Payments, 2013	52
Benefit Payments, 2014	49
Benefit Payments, 2015	47
Benefit Payments, 2016	44
Benefit Payments, 2017 - 2021	189
Subsidy Receipts, 2012	11
Subsidy Receipts, 2013	11
Subsidy Receipts, 2014	9
Subsidy Receipts, 2015	9
Subsidy Receipts, 2016	7
Subsidy Receipts, 2017 - 2021	$ 32

Postretirement Benefits (Estimated Total Future Postretirement Benefit Payments, Net Of Participant Contributions And Estimated Future Medicare Part D Subsidy Receipts) (Details) (U.S. Postretirement Benefit Plans [Member], USD $)
In Millions, unless otherwise specified

Dec. 31, 2011

U.S. Postretirement Benefit Plans [Member]

Defined Benefit Plan Disclosure [Line Items]

Benefit Payments, 2012

$ 55

Benefit Payments, 2013

Benefit Payments, 2014

Benefit Payments, 2015

Benefit Payments, 2016

Benefit Payments, 2017 - 2021

189

Subsidy Receipts, 2012

Subsidy Receipts, 2013

Subsidy Receipts, 2014

Subsidy Receipts, 2015

Subsidy Receipts, 2016

Subsidy Receipts, 2017 - 2021

$ 32

- Details

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the aggregate benefits expected to be paid in the five fiscal years thereafter (the aggregate amount of benefits expected to be paid in years 6 through 10 after the date of the latest statement of financial position).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInFiveFiscalYearsThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of the benefits expected to be paid in Year 5.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of the benefits expected to be paid in Year 4.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of the benefits expected to be paid in Year 1.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearOne
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of the benefits expected to be paid in Year 3.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of the benefits expected to be paid in Year 2.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate amount for the next five fiscal years following the first five fiscal years (that is the aggregate of fiscal years six through ten) following the balance sheet date of the prescription drug subsidy receipts expected to be received.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS106-2

-Paragraph 22

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

+ Details

Name:	us-gaap_PrescriptionDrugSubsidyReceiptsFiveFiscalYearsThereafter
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 5 after the balance sheet date.

+ References

+ Details

Name:	us-gaap_PrescriptionDrugSubsidyReceiptsYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 4 after the balance sheet date.

+ References

+ Details

Name:	us-gaap_PrescriptionDrugSubsidyReceiptsYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 1 after the balance sheet date.

+ References

+ Details

Name:	us-gaap_PrescriptionDrugSubsidyReceiptsYearOne
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 3 after the balance sheet date.

+ References

+ Details

Name:	us-gaap_PrescriptionDrugSubsidyReceiptsYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 2 after the balance sheet date.

+ References

+ Details

Name:	us-gaap_PrescriptionDrugSubsidyReceiptsYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant